1. Field of the Invention
This invention relates to sliders for hard disk drives, and more particularly to self-loading negative pressure air bearing sliders for use with rotary actuators.
2. Background Information
The read-write head is embedded in a slider. The slider floats on a thin air bearing a very short distance above the rotating disk surface. Typically, the slider has a trailing end in which the read-write head is mounted.
Disk rotation drags air under the slider. The air bearing is generated between the flying slider and the rotating disk. The skin friction on the air bearing surface of the slider creates an aerodynamic lifting force. This causes the slider to lift and fly above the disk surface. Today, most conventional sliders include a sub-ambient pressure region around slider centroid. This sub-ambient pressure zone develops negative pressure that counteracts the aerodynamic lifting force developed along the air bearing surface. These lifting and sub-ambient forces combine to stabilize slider's flying environment.
In the hard disk drive industry, there is a continuous economic incentive for greater bit density on the disk surfaces. This places a strong emphasis on extremely narrow flying gaps between sliders and the rotating disk surfaces over which they fly.
Today, many hard disk drives employ sliders designed to operate at some level of interference between the slider and the contaminating particles found on or near the rotating disk surface.
Because current conventional sliders fly very close to the disk surface, the particle contamination between the slider and the rotating disk surface is a serious problem, affecting the reliability of data access operations.
Because of the small size of these particles, they can easily be taken up into the air flow. They flow along with the main air stream, interacting with the slider and the rotating disk interface. The particles tend to accumulate on the slider surface, often changing the characteristics of the slider to rotating disk surface interface. This tends to destabilize how the slider flies over the rotating disk surface, and may cause abrasion on the disk surface. The abrasion may result from scratches on the disks, embedding some of these particles in the rotating disk surface. Both of these effects can seriously reduce the operational reliability of the hard disk drive.
While it would be best if there were no floating particles inside of the hard disk drive, it is not possible to make an economical, completely clean, hard disk drive. Additionally, normal operation of a hard disk drive may generate new particles.
What is needed is substantial reduction of contamination of the slider-rotating disk surface interface by safely rejecting these floating particles between the flying slider and the rotating disk, especially around the read-write head.
What is needed is a flying head slider experiencing less failure from particle contamination, in particular less abrasive wear and fewer disk surface scratches.
Magnetic spacing modulation refers to modulations in the magnetic field between the read-write head and a track being accessed on the rotating disk surface. These modulations result from collisions of particles with the slider, which causes the flying height to vary. A slider is needed, with less magnetic spacing modulation and improved stability in its flying over the rotating disk surface.